Wet cleaning is a frequent and critical operation in the manufacture of a workpiece, such as a magnetic recording media, semiconductor wafer or LCD panel. Wet cleaning generally entails introducing a liquid, aqueous or otherwise, to the surface of the workpiece. Both throughput and cleaning efficiency of a wet clean are important considerations because throughput determines equipment cost/workpiece, which should be minimized while cleaning efficiency determines workpiece yield, which should be maximized.
Wet cleaning generally also entails drying the workpiece. Typically, a drying operation is performed by first submerging the workpiece in a volume of liquid, such as deionized ultrapure water, and then displacing the workpiece from the liquid volume to a gaseous volume to dry the liquid from the surface of the workpiece. FIG. 1 illustrates a plan view of a magnetic recording media substrate 130 which has been wet cleaned and dried in such a manner during a media fabrication process. A residue stain 131 is depicted on the magnetic recording media substrate 130. Such stains are frequently caused by improper drying which may occur for example when the workpiece is pulled, or withdrawn, from the liquid during the drying operation and the liquid meniscus at the liquid interface breaks poorly and leaves behind a residue.
While it is known that such residue stains are detrimental to workpiece yield, throughput of a dryer can suffer greatly if the pull speed of the workpiece is reduced significantly to reduce ripples in the liquid interface or to otherwise improve other undesirable meniscus behavior in an effort to mitigate yield loss from residue staining. For example, a mere 20 second increase in the dryer process time can translate into a 200 parts/hour throughput reduction.